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Chainlines for 2 wheeled ‘bents

Not to leave the 2 wheelers out of the collection, here are some chain lines of two wheel recumbents.

DSC02373

Says Bruce: Stephen (tennbent) and I wanted to eliminate the inherent problems on his Optima Baron that also exist with the chainlines on a lot of mid and low racers. The picture above shows the chain crossover between idlers.

DSC02391

The picture above shows the revised chainline, with crossover issue resolved. First, we wanted to clear the front tire/fork, and also to eliminate any chain cross-overs. We also did some other minor chainline mods to clean up the line. I won’t go into all of the details of HOW we did this, but the pics show the results. And, it works quite well. Stephen says it quieted the whole chainline a lot.

Admittedly, the change added another small bend in the power chain line, which technically adds pedal effort, but Stephen says he can’t feel any extra effort, and most folks won’t either.  Maybe Lance Armstrong could feel it.  The extra bend is about what most trikes experience in chain line bend.  Bruce

1

The picture above shows one wheelbase-version of the Musashi, with chain crossover problems.
469364fa2483140ed15bcf817c696a0d483c3904
Another version of the Musashi, with chain crossover issues.

Chainlines, Idlers, and Tubes, oh my!

Chain lines on trikes seem to generate a lot of experimenting and novel approaches.  The pictures below show a bunch of different approaches to making a chainline quiet and efficient, on all Catrikes I believe.

Hopefully the creators of these setups or those who have tried similar ones will comment on the likely quietness and efficiency of each of these setups.  Send additional pics of chainlines of any type of bent, and I’ll post them.

Bruce's speed.40

Above: Bruce’s Speed. Bruce says this is the cleanest, quietest, most efficient setup he has used.   

dr duk

Above: Dr. Duk’s version of chain tubes.  Says Bruce: “…shows the easiest, and best way to give the tubes the loosest float possible, and this is a good thing.”

Flying Tiger

Above: Flying Tiger’s version

Bruce's orange speedBruce’s orange Catrike.  “This is the overly complex, and expensive, chainline that I tried on two of my Speeds.  I had four goals for it:  lift the return chain higher off the ground, push the power chain under the front axle, raise everything above the bottom of the main frame tube, and eliminate all tubes.  It did all four quite well, but at the expense of expense and more noise.  Both trikes are back to a single tube on the return chain, with just some tape on top of the axle to protect against the power chain slap. ”

Jerry McKee.50

another trike set up, by Jerry Mckee.

Bruce: “Jerry McKee’s is close, but the idlers should have been placed behind the front axle. Also, by pushing the power chain under the front axle, you alter the angle of the power chain to the der post and der. This can hurt the shifting, and at the least, it limits how small you can go on the small ring. I know this because on my Tony Trike, I couldn’t go smaller than a 30 tooth ring when I did this arrangement.”

John Rooker.50

Above: John Rooker’s Expedition.   Says John: “I have the same setup on my present Trail.  This is simple, effective, quiet and costs almost nothing once you’ve purchased the return side idler.”

phantomexp_idlers

Utah Trikes photo, on an Expedition.  “…just insanely wrong! All of the Expo’s cherished ground clearance is lost with that arrangement. That idler should have been placed in front of the axle, as Pat Franz has designed those clamp-ons to be placed.”

photofinish.80

photofinish

photofinish 3.80

photofinish 2

photofinish.80

photofinish 3

Bruce’s opinion – “Photofinish’s setup is a good example of a common myth about chainlines, that running the return chain in a straight line gives less drag. Wrong! It increases the drag compared to a slightly curved tube run underneath. If you let the chain hang naturaly with no tube, it has no frictional drag, so what better way to “tube” it than to run it through a tube that follows it’s natural curve as much as possible. Ideally, if the tube’s curve matches the chain’s curve, the tube will not be supporting the chain at all, and therefore will not induce any drag. But, if you lift the chain up and run it through a straight tube above where it wants to hang naturally, the tube is then carrying all of the chain’s weight, and that creates a LOT of drag, not to mention more noise. It may look cool, but it will cost you in pedal effort and extra noise. If you look at the first pic of my Holey Spokes, the tube has been curved to match the natural droop of the return chain as close as possible. With generous flares, it is almost silent all the time.”

rexpedition.50

rexpedition

Bruce’s Opinion – “pretty close to stock and about the best you can get. Quiet and efficient!”

Utah trike

another one from Utah Trike

HP velocotech lg_chaintube_sideangle

Chain tube attachment by HP – Velotechnik, sold at Hostel Shoppe. A long spoke held under the idler bolt and tied to the tube as far along the tube as possible will allow the tube to move around as much as it needs to in reaction to chain movement, with very little restriction.  The longer the spoke, the more flex is would have.  

tcycle floating tube holder

Terracycle floating tube holder.  They also sell flared sections of chain tube.  Although the floating tube holder is cool, the bike has chain routing and crossover issues. Without tubes the chain would rub itself, causing it to “snag” on itself as the pin ends catch each other.  Also, the chain runs along the side of the fork, rubbing it almost constantly.  Even with a tube, the tube rubs the fork.  It also limits the turn radius, because the tire will rub the chain with very little turn input.  Bruce  

phattkat1

PhattKat’s setup, from his blog. Note the attachment of both the power side tube and the return side tube to the idler.  These attachments look solid. Also full coverage of the chains, as shown below.  How does one keep a chain so clean!!??  My trike is a mess by comparison.

Phattkat2

Phatkatts chain tubes.